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A Large Number or BUS_ERR Alarms Are Reported due to Unstable Upstream Signals

Publication Date:  2012-07-25 Views:  35 Downloads:  0
Issue Description
The NE CXL in the network of an overseas representative office reports the BUS_ERR alarm transiently and repeatedly, and the alarms are cleared automatically later. 
Alarm Information
BUS_ERR A0132-AAR-801-81-CXL-OTHER 2008-2-14 4:45 2008-2-14 4:46 0x0c 0x01 0x04 0x01 0xff
BUS_ERR A0132-AAR-801-81-CXL-OTHER 2008-2-14 4:46 2008-2-14 4:46 0x0c 0x01 0x04 0x01 0xff
BUS_ERR A0132-AAR-801-80-CXL-OTHER 2008-2-14 4:46 2008-2-14 4:46 0x0c 0x01 0x04 0x01 0xff 
 
Handling Process
The BUS_ERR alarm is caused by the instability of the optical fiber in the network. 
Root Cause
The engineer analyzes the BUS_ERR alarm first:
BUS_ERR A0132-AAR-801-81-CXL-OTHER 2008-2-14 4:46 2008-2-14 4:46 0x0c 0x01 0x04 0x01 0xff
The fourth parameter “0x01” indicates the status of the service that reaches the cross-connect board. Because the parameter is reported for multiple times, it indicates that the service is unstable.
The first parameter indicates the line board that the faulty service reaching the cross-connect board originates from. In this alarm, the 0x0C indicates the board in slot 12.
The second parameter indicates the bus number. In this alarm, the parameter corresponds to the first optical port of the 12-SLQ1.
The third parameter indicates the specific service type and the error type. If the first BIT is 1, it indicates the OOF; if the second BIT is 1, it indicates the B1 error bit. For example, if the parameter is 0x06, because both the first and second bits are 1, it means that the OFF and B1 are detected.
Based on the above information, it can be concluded that the service from the first optical port of the 12-SLQ1 is unstable. However, the ROOF alarm is transiently reported in the OptiX OSN 1500 line and the corresponding optical port on the NE connected to the OptiX OSN 1500 12-SLQ1-1 is also very unstable. The engineers check the records of the board that obtain the following information:
1657 11 ROOF critical end 2008-2-14 4:17 2008-2-14 4:17:52 0x01ffff01
1658 11 MS_REI warning end 2008-2-14 4:17 2008-2-14 4:17:52 0x01ffff01
1659 11 HPREI warning end 2008-2-14 4:17 2008-2-14 4:17:52 0x01ffff01
1662 11 RLOS critical end 2008-2-14 4:18 2008-2-14 4:19:08 0x01ffff04
1665 11 HPREI warning end 2008-2-14 4:19 2008-2-14 4:19:13 0x01ffff01
1666 11 HPREI warning end 2008-2-14 4:19 2008-2-14 4:19:21 0x01ffff01
1667 11 MSRDI minor end 2008-2-14 4:19 2008-2-14 4:19:23 0x01ffff01
1668 11 HPREI warning end 2008-2-14 4:19 2008-2-14 4:19:34 0x01ffff01
1669 11 HPREI warning end 2008-2-14 4:21 2008-2-14 4:21:31 0x01ffff01
1671 11 ROOF critical end 2008-2-14 4:25 2008-2-14 4:25:21 0x01ffff02
1673 11 HPREI warning end 2008-2-14 4:25 2008-2-14 4:25:21 0x01ffff01
1675 11 HPREI warning end 2008-2-14 4:26 2008-2-14 4:26:58 0x01ffff01
1679 11 ROOF critical end 2008-2-14 4:41 2008-2-14 4:41:03 0x01ffff02
It can be seen that a large number of OOF events is reported. This finding further confirms that the BUS_ERR alarm occurred in the downstream site is caused by the instability of the optical fiber line. 
 
Suggestions
The optical fiber connection status between the optical boards of two NEs must be improved. 

END